BRAINLIEST! Which of the following math statements contain variable(s)? Check all that apply.

A. 13 - x = 9
B. 1 + 6 = 7
C. 15 - 5 = ___
D. ? + 7 = 12

You are making a battery for a science project. you have copper wire for your first electrode. you need to choose a conductor, a second electrode, and a device to plug into your battery. you have already chosen a lemon conductor. complete each statement below about the options that include a lemon conductor.

You need to solve a system of equations. you decide to use the elimination method. which of these is not allowed? 3x - 2y = 7 3x + 4y = 17 equation 1 equation 2

Drag the tiles to the correct boxes to complete the pairs. using the properties of integer exponents, match each expression with the correct equivalent expression.